Monday, 11 January 2010

The central processing unit in a computer is sometimes referred to (incorrectly in my opinion) as a microprocessor. In some circles also known as a CPU microprocessor (which is a little bit long-winded as well as over-the-top). The CPU is the component within a computer system that performs instructions initiated by a computer program. In very basic terms the CPU carries out computer functions or low level calculations. To reiterate, the CPU executes a sequence of instructions (a program) from the computer's memory. You don't need to know how the CPU works to build a computer but you need to know which one is compatible with your motherboard and components.

Researching the best CPU can be a little bit confusing for the beginner to computer building. This is because central processing units are manufactured in a multitude of different shapes, clock speeds, and form factors (or sizes). The first point to consider is that there are only two major brands of CPU to consider. These are Intel (you should have heard of this company) and their main rival AMD who you should also be familiar.
Intel are well known for their Celeron, Pentium and Core I processors. AMD built their reputation around their Sempron, Athlon and Phenom processors.

Intel also manufactures a range of XEON processors for servers and workstations. Intel has also developed the ATOM processor for small devices including laptops and/or notebooks. Intel Processors

*Please note that this is how the product lines looked at the time of writing this article. The computer industry develops products at quite a fast pace and undoubtedly this page will soon (if not already) be out of date. This is why I've included links to both manufacturers’ product pages on their respective websites. If the links are broken please alert me to the fact by leaving a comment.

How to decide which is the best CPU for your new computer build?
Choosing a central processing unit can be a daunting task for the beginner to building computers. The decision has to be made alongside selecting a motherboard. This is because the components have to be compatible so that they work together. An early decision that has to be made is whether to build an AMD or Intel powered computer. If you want to build an AMD CPU powered computer you will need to use an AMD compatible motherboard. If you decide to build an Intel CPU powered system you will need to use an Intel compatible motherboard.

As always Budget plays an important part in most computer builders plans. CPUs can be catagorised into simple price ranges of low, middle and high based on their specification. AMD sempron and Intel Celeron processors are low end (and low budget) components. This makes them suitable for basic machines built for simplistic tasks such as home computing. To build a computer capable of taking on more comprehensive tasks you will need at least a mid range processor. It is possible to find some real bargains in this range of products. In fact some builders believe that these are actually the best processors because they are stable. High end expensive processors are at the cutting edge of technology. They are very popular with hardcore gamers and computer builders because they offer the fastest speeds. The drawback being that in some cases using largely untested components may involve extensive troubleshooting of any problems that arise.

How to Install the CPU
Whether building a new computer or upgrading a CPU in an old one, installing the CPU is generally a simple task. The CPU connects directly to an interface on the motherboard most commonly called a socket. Once the CPU is positioned into the socket a heat sink is added and this sits directly above it on the motherboard. A cooling fan is then fitted to the heat sink to absorb and dissipate heat by thermal contact. Retail versions of CPU are usually supplied with all these components ready assembled with thermal paste pre-applied. If your CPU is not a retail version (CPU only) you will probably need to buy a heat sink, thermal paste and cooling fan separately. The cooling fan is used to draw air through the heat sink which makes it work more efficiently. A more expensive alternative is to use a water cooling system. This provides a more effective method of cooling where the CPU has been heavily overclocked.

Warning: Remember to take Electrostatic discharge precaution when working on any computers. This means wearing an anti-static wrist band and/or using anti-static mats. Failure to do so may lead to damage to computer components (which is not always immediately evident).

When the time comes to install the CPU into the motherboard carefully remove all the packaging. Remove the CPU socket cover from the motherboard and align the CPU to the socket. A modern processor (such as an Intel Core I7) will only fit into the socket the correct way round. Place it so that the interface faces downwards. Use the spring loaded clip on the motherboard to lock the CPU in position. For some processors these clips can be very stiffly sprung - a little bit of force may be required to lock the processor down. It is important to ensure that the correct amount of thermal paste is applied to the processor before the heat sink is connected. Use a very small dab of thermal paste (also called thermal grease) and spread it thinly over the area. Add the heat sink and fan to the processor and connect the power supply. A modern processor takes its own power supply which has to be connected to the correct interface on the motherboard. The processor fan will require connecting to the CPU fan interface on the motherboard. On most motherboards the connection interfaces are clearly written on the board.

[on some older motherboards the heat sink clips to the motherboard and this mechanism locks the CPU into position]

Finally, ensure that the cables are tidy and do not obstruct the blades of the CPU cooling fan. When wiring ensure that you always take the shortest possible route. Use cable ties to keep cables tidy inside the computer case. This may not seem important but it actually makes a lot of difference to air flow and can be important for avoiding electrical interference. Obviously, it looks better too!